Agenus to Present Botensilimab Data in Oral Plenary Session at the Society of Gynecologic Oncology 2023 Annual Meeting on Women’s Cancer

Agenus (Nasdaq: AGEN), a clinical-stage company with a pipeline of therapies designed to activate the body's immune system to fight cancer and infections, today announced plans to present updated data on its lead program botensilimab (Fc-enhanced anti-CTLA-4), at the Society of Gynecologic Oncology (SGO) 37th Annual Meeting on Women’s Cancer, to be held March 25-28 in Tampa, FL. Updated data from an expansion cohort of the Phase 1 study of botensilimab in combination with balstilimab (anti-PD-1) in patients with recurrent platinum refractory/resistant ovarian cancer will be presented at an oral plenary session on Monday, March 27 th at 9:18am ET.

Presentation Details:

Abstract Title: Botensilimab, a Novel Innate/Adaptive Immune Activator, plus Balstilimab (Anti-PD-1) in Patients with Recurrent Platinum Refractory/Resistant Ovarian Cancer (NCT03860272) Abstract ID: 2 Presenting Author: Bruno Bockorny, MD, Harvard University, Beth Israel Deaconess Medical Center Details: Scientific Plenary V: Progress: Hitting Our Targets, 3/27/2023, 9:00am – 9:45am ET

The complete abstract will be available the morning of the presentation at 9:00am ET. Data presented at the conference will be available to view in the Publications section of the Agenus website ( https://agenusbio.com/publications ) following the SGO Conference.

About Botensilimab Botensilimab is a novel, multifunctional CTLA-4 antibody that has been designed to extend clinical benefits to “cold” tumors that do not respond to currently approved immunotherapy-only regimens. In addition to binding to the CTLA-4 receptor, its FC-enhanced structure induces memory immune response, downregulates regulatory T cells, and delivers better priming and activation of T cells, thereby amplifying immune responses.

In a Phase 1b clinical study of more than 300 patients, botensilimab has demonstrated clinical responses in nine solid tumor cancers, either alone or in combination with Agenus’ PD-1 antibody, balstilimab. Agenus is conducting global, randomized Phase 2 trials in microsatellite-stable colorectal cancer (MSS CRC), pancreatic cancer, and melanoma as part of its ACTIVATE trial program. A global Phase 3 trial in MSS CRC is planned to launch in 2023.

About Agenus Agenus is a clinical-stage immuno-oncology company focused on the discovery and development of therapies that engage the body's immune system to fight cancer and infections. The Company's vision is to expand the patient populations benefiting from cancer immunotherapy by pursuing combination approaches that leverage a broad repertoire of antibody therapeutics, adoptive cell therapies (through its subsidiary MiNK Therapeutics), and adjuvants (through its subsidiary SaponiQx). The Company is equipped with a suite of antibody discovery platforms and a state-of-the-art GMP manufacturing facility with the capacity to support clinical programs. Agenus is headquartered in Lexington, MA. For more information, please visit www.agenusbio.com and our Twitter handle @agenus_bio. Information that may be important to investors will be routinely posted on our website and Twitter.

Forward Looking Statements This press release contains forward-looking statements that are made pursuant to the safe harbor provisions of the federal securities laws, including statements relating to the use of botensilimab, for instance, statements regarding therapeutic benefit and efficacy, mechanism of action (including validation of mechanism of action), potency, durability, and safety profile (including the absence of specific toxicities) of the Company’s therapeutic candidates, both alone and in combination with each other and/or other agents (e.g., botensilimab and/or balstilimab in combination); and any other statements containing the words "may," "believes," "expects," "anticipates," "hopes," "intends," "plans," "forecasts," "estimates," "will," “establish,” “potential,” “superiority,” “best in class,” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially. These risks and uncertainties include, among others, the factors described under the Risk Factors section of our most recent Quarterly Report on Form 10-Q or Annual Report on Form 10-K filed with the Securities and Exchange Commission. Agenus cautions investors not to place considerable reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this press release, and Agenus undertakes no obligation to update or revise the statements, other than to the extent required by law. All forward-looking statements are expressly qualified in their entirety by this cautionary statement.

Contact Agenus Inc. Zack Armen Head of Investor Relations 917-362-1370 zack.armen@agenusbio.com